1. Field of the Invention
The present invention relates to a loader that places a head of a hard disk drive adjacent to a disk.
2. Background Information
Hard disk drives contain magnetic transducers which write and read information onto a rotating magnetic disk(s). The transducers are typically integrated into a head that is assembled to a flexure arm. Some heads contain a transducer to write information and a separate transducer to read information. The read transducer may be constructed from a magneto-resistive (MR) material. The head and arm are commonly referred to as a head gimbal assembly (HGA). Each HGA is attached to an actuator arm and a voice coil motor that can move the heads across the surfaces of the disk(s).
Each head has an air bearing surface which cooperates with an air flow generated by the rotating disk(s) to create an air bearing between the disk and the transducer. The air bearing prevents mechanical wear between the head and the disk surface. It is desirable to minimize the length of the space which separates the transducer and the disk to maximize the magnetic coupling between the two components. Heads are therefore designed create an optimal space between the transducer and the disk.
It is desirable to measure the height of an air bearing created by a head. The height is typically measured with an optical system that places a head adjacent to a rotating transparent disk. A light beam is then directed through the transparent disk and reflected from the head back to a photodetector. The detected light is used to compute the "flying height" of the head.
Flying height testers typically include a loader which places the head adjacent to the transparent glass disk. The step of loading the head typically requires moving the head radially across a portion of the disk. Some flying height testers include a blade or finger that engages the flexure arm so that the head will not scratch the glass as the head moves across the disk. A scratch on the glass may distort the light reflected through the disk.
Most flexure arms have bent rail portions to increase the stiffness of the arms. The loader blades of the prior art typically extend across the rails in a direction that is perpendicular to the longitudinal axis of the flexure arms. The flexure arms are located in close proximity to the glass disk when the head is loaded onto the disk. There is typically not enough space for a blade or finger between the rails and the disk when the head is loaded. For this reason the blade must be retracted from the flexure arm before the head is loaded onto the disk. Retracting and reinserting the blade may bend and damage the flexure arm. Additionally, the loader requires an additional mechanism to retract and reinsert the blade. It would therefore be desirable to provide a loader blade that does not have to be removed after a head is loaded onto a disk.